B1691 – OBD-II DTC

OBD-II DTC B1691 – Autolamp Delay Circuit Short To Battery

DTC B1691 meaning

DTC B1691 refers to a diagnostic trouble code indicating a problem with the autolamp delay circuit. Specifically, it signifies a short circuit to battery voltage within the autolamp delay circuit. This circuit is responsible for controlling the automatic operation of the vehicle’s headlights based on ambient light conditions.

DTC B1691 symptoms

Common symptoms associated with DTC B1691 may include:

• Headlights not functioning as intended
• Headlights staying on longer than normal
• Headlights not turning on automatically
• Dashboard warning lights illuminated

DTC B1691 causes

Several factors can lead to the occurrence of DTC B1691, including:

• Wiring issues such as frayed or damaged wires
• Faulty connectors or terminals
• Defective autolamp control module
• Short circuits in the autolamp delay circuit
• Corrosion in electrical connections

DTC B1691 seriousness

DTC B1691 is considered a moderate issue. While it may not immediately affect the drivability of the vehicle, it can lead to safety concerns due to improper headlight operation. This can increase the risk of accidents, especially in low-light conditions.

How to diagnose DTC B1691

To diagnose DTC B1691, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the DTC.
2. Inspect the wiring and connectors related to the autolamp delay circuit for any visible damage.
3. Check for continuity in the circuit to identify any breaks or shorts.
4. Test the autolamp control module for proper operation.
5. Clear the DTC and perform a road test to see if the code reappears.

How to fix DTC B1691 step-by-step instructions

To fix DTC B1691, follow these steps:

1. Inspect and repair any damaged wiring or connectors in the autolamp delay circuit.
2. Replace any faulty components, such as the autolamp control module, if necessary.
3. Ensure all connections are clean and free of corrosion.
4. Recheck the circuit for continuity and proper voltage.
5. Clear the DTC using an OBD-II scanner and perform a test drive to confirm the issue is resolved.

How to erase DTC B1691

To erase DTC B1691, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the DTC menu on the scanner.
4. Select the option to clear or erase the trouble codes.
5. Confirm the action and wait for the scanner to indicate that the codes have been cleared.

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